KT is paying attention to 'RIS' as a technology that can efficiently expand network coverage.

KT announced on the 27th that it has developed a 'Reconfigurable Intelligent Surface (RIS) technology' that operates in the 3.5GHz 5G wireless communication frequency band and the 12GHz KT Skylife satellite frequency band with a research team from the Department of Electrical and Information Engineering at Seoul National University. KT unveiled this technology at MWC 2024.

RIS is a technology that can direct the reflection and transmission of radio waves in a desired direction. By introducing RIS to the exterior walls of a building, it becomes possible to transmit and receive signals by transmitting high-frequency band frequencies without exposing wireless communication equipment to the outside of the building. Helps build network infrastructure more efficiently.

RIS, developed by KT and the research team of Professor Oh Jeong-seok of the Department of Electrical and Computer Engineering at Seoul National University, is characterized by passing through 5G wireless communication frequencies and KT Skylife satellite frequency bands in a small area in addition to 6G candidate frequencies.

KT has been developing RIS materials and technology that operate in the 28GHz band, which is a millimeter wave (mmWave) band, as well as the 8GHz and 15GHz bands, which are candidate frequency bands for 6G. The frequency bands currently used in 5G have relatively low frequencies, so the possibility of commercialization was low due to issues such as the need for a large RIS sample area.

The newly developed RIS utilizes new surface design technology and structure to simultaneously secure a wide transmission angle that is refracted more than 90 degrees (negative refraction angle) relative to the direction of travel and high transmittance. A wide transmission angle is advantageous for improving indoor wireless quality. It is made of transparent material, so it can be attached to the glass window of a moving vehicle or manufactured as an integral part, making it easy to install.

To verify the universality of their own RIS technology, KT and Seoul National University attached RIS to a vehicle window and confirmed that wireless signals coming in from a direction perpendicular to the vehicle's direction of movement, such as 5G waves from a communication tower on the outskirts of a highway or KT Skylife satellite signals, were refracted inward.

KT will continue to cooperate with equipment manufacturers and material/parts companies to apply the RIS technology it recently acquired to building windows and vehicle windows. In addition, we plan to secure technological leadership in the 6G wireless communications field by continuously discovering element technologies applicable to various wireless network environments, such as RIS.

Professor Jeong-Seok Oh of the Department of Electrical and Computer Engineering at Seoul National University said, “While most of the existing research and demonstrations on transparent RIS have focused only on improving transmission loss, this RIS technology and verification are significant in that they have proven for the first time that communication coverage can be significantly improved by bending radio waves in any direction even under constraints on transparent materials and process conditions.”

“We expect the RIS technology we have developed this time to improve the quality of wireless services within mobile devices,” said Lee Jong-sik, executive director of KT’s Network Research Center. “It will contribute to the construction of 6G networks by strengthening our leadership in new wireless communication technologies.”